MEMORANDUM FOR THE HEADS OF EXECUTIVE DEPARTMENTS AND AGENCIES
SUBJECT: Plain Language in Government Writing
"The Federal Government's writing must be in plain language. By using plain language, we send a clear message about what the Government is doing, what it requires, and what services it offers. Plain language saves the Government and the private sector time, effort, and money."
Plain language can be understood by YOUR reader at first reading. It doesn't mean writing for a certain grade level - it means organizing and writing for your reader. Writing in plain language saves time and money for writers and readers.
Plain language matches the needs of the reader with your needs as a writer, resulting in effective and efficient communication. It is effective because the reader can understand the message. It is efficient because the reader can read and understand the message the first time.
Also: LegalWriting.net Plain language produces clear, concise, and readable documents
And then for no reason ,other than most writing is twaddle, here's a review of: